Magnetic Resonance Imaging and Computed Tomography Findings in Pediatric Giant Cell Glioblastoma

Excerpt

Giant cell glioblastoma (GCG) is considered to be a subtype of glioblastoma multiforme (GBM). This malignant tumor of glial origin is a grade IV tumor according to the current classification of the World Health Organization (WHO, [1]) and accounts for approximately 5% of GBMs and 0.8% of all brain tumors [2]. In pediatric patients supratentorial tumors are less common than infratentorial tumors with a ratio of approximately 1:2. The GBMs account for 7–9% of all intracranial tumors and 0.6–7.9% of all GBMs occur during childhood [3]. These statistics demonstrate that GCG is an exceedingly rare tumor mainly described in isolated case reports or series with a predilection for younger patients [2,4]. The GCGs arise from white matter, as do the common GBMs and have a tendency to involve the frontal and temporal lobes [2,5]. The higher predilection for the cerebral hemispheres than a typical GBM, probably in addition to histological variations, may be responsible for the better prognosis as the location means that gross total resection is more frequent. The tumor is macroscopically well-circumscribed and histologically shows numerous bizarre multinucleated giant cells with an abundant reticulin network and a high frequency of p53 mutations [6,7]. In general terms GBM has a poor prognosis with a mean survival time ranging from 12–15 months in adults [8]. In pediatric patients with high grade astrocytoma the outcome is slightly better but still remains poor with survival times ranging from 15–42 months [9,10]. In standard GBM treatment protocols tumor resection is followed by irradiation and DNA alkylating chemotherapy. Adding temozolomide as a chemotherapy drug significantly improved outcome in newly diagnosed GBM [11,12] and the median survival time improved from 12.1 to 14.6 months and the 2-year survival rate reached 25.6% compared to 10.4% previously when adding temozolomide to standard GBM treatment protocols [13,14]. Other factors associated with decreased survival in GBM include but are not limited to larger tumor size [15], higher age [16] as well as bilateral location [17]. The GCG is associated with longer survival times compared to GBM, ranging from 15 months up to 17 years in adults [5,18] and ranging from 14 months up to 12 years in children [4,19].One case report also reported a long-term survival with a late transformation to gliosarcoma [6]. …